Method for manufacturing a negative electrode, negative electrode, galvanic cell and use of the galvanic cell

Abstract

A method for manufacturing a negative electrode of a galvanic cell, a negative electrode of a galvanic cell, and a galvanic cell are provided, and a use of the galvanic cell is proposed. The method is characterized in that a first planar metal structure is pressed into the carbon coating of a second planar metal structure, and a plurality of openings on the planar underside of the first planar metal structure are at least partially filled with carbon from the carbon coating of the second planar metal structure. Here, either the first planar metal structure or the second planar metal structure contains or consists of aluminum or an aluminum alloy.The inventive method enables the simple and cost-effective production of a negative electrode that exhibits high energy density, high power density and high cycle stability.

Description

[0001] A method for manufacturing a negative electrode of a galvanic cell, a negative electrode of a galvanic cell, and a galvanic cell are provided, and a use of the galvanic cell is proposed. The method is characterized in that a first planar metal structure is pressed into the carbon coating of a second planar metal structure, and a plurality of openings on the planar underside of the first planar metal structure are at least partially filled with carbon from the carbon coating of the second planar metal structure. Here, either the first planar metal structure or the second planar metal structure contains or consists of aluminum or an aluminum alloy.The inventive method enables the simple and cost-effective production of a negative electrode that exhibits high energy density, high power density and high cycle stability.

[0002] The production of lithium-aluminum-based negative electrodes for galvanic cells is known in the prior art. It is known to process aluminum as a powder and also to coat it as a powder (CN 107623119 A). This has the disadvantage that the processing is complex, as a coating process is part of the manufacturing process. Furthermore, the use of aluminum powder has the disadvantage that the cycle stability of the produced negative electrodes is low and the capacity contribution of aluminum is not sufficiently utilized, thus making the achievable energy density in need of improvement. Moreover, the known lithium-aluminum-based negative electrodes do not exhibit a high power density. In addition, the known aluminum-based negative electrodes show high volume surges during lithiation and delthiation, which results in insufficient cycle stability.Furthermore, the known aluminum-based negative electrodes exhibit high nucleation overpotentials during LiAl alloy formation. In addition, the manufacturing processes for such negative electrodes are costly if they are coated with metallic lithium or a lithium alloy before use in a galvanic cell, and are also difficult to handle when working with metallic lithium.

[0003] Furthermore, the production of carbon-silicon-based negative electrodes is known in the prior art. It is known to process silicon as a powder and also to coat it as a powder (Jin, Y. et al., Advanced Energy Materials, Vol. 7, Issue 23, 1700715, pp. 1-17). This has the disadvantage that the cycle stability of the produced negative electrodes is low and the capacity contribution of silicon is not sufficiently utilized, thus making the achievable energy density in need of improvement. In addition, the manufacturing processes for such negative electrodes are often cost-intensive and also difficult to handle when working with metallic lithium.

[0004] Against this background, the object of the present invention was to provide the simplest and most cost-effective method possible for producing a negative electrode for a galvanic cell that exhibits high cycle stability, high energy density, and high power density. Furthermore, a negative electrode with high cycle stability, high energy density, and high power density was to be provided. In addition, a galvanic cell characterized by high cycle stability, high energy density, and high power density was to be provided. Finally, a use for the galvanic cell was to be proposed.

[0005] The problem is solved by the method with the features of claim 1, the negative electrode with the features of claim 10, the galvanic cell with the features of claim 19, and the use with the features of claim 20. The dependent claims describe advantageous embodiments of the invention.

[0006] According to the invention, a method for producing a negative electrode suitable for use in a galvanic cell is provided, comprising a) Providing a first planar metal structure having a planar top and a planar bottom and having a certain height in a direction perpendicular to the top and bottom, wherein the first planar metal structure has a plurality of openings on its planar bottom extending from the bottom towards the top of the first planar metal structure; b) Providing a second planar metal structure having a planar top and a planar bottom and having a certain height in a direction perpendicular to the top and bottom, wherein at least the top of the second planar metal structure has a carbon coating, wherein the carbon coating has a planar top and a planar bottom and has a certain height in a direction perpendicular to the top and bottom, and wherein the bottom of the carbon coating contacts the top of the second planar metal structure;characterized in that the first planar metal structure is pressed at least into the carbon coating of the second planar metal structure and the plurality of openings on the planar underside of the first planar metal structure are at least partially filled with carbon from the carbon coating of the second planar metal structure, wherein the first planar metal structure or the second planar metal structure contains or consists of aluminum or an aluminum alloy.

[0007] The inventive method enables the simple and cost-effective production of a negative electrode that exhibits high energy density, high power density and high cycle stability.

[0008] The process is simpler and the handling is improved, since no lithium metal is used in the production of the negative electrode (lithium is only deposited in the negative electrode when the negative electrode is used in a galvanic cell).

[0009] The high energy density (i.e., capacity) compared to known graphite-based negative electrodes results from the aluminum in the negative electrode. Compared to known aluminum-based negative electrodes, the higher energy density (capacity) also results from the use of aluminum in the form of a sheet-like metal structure instead of aluminum powder. The sheet-like metal structure of aluminum is also a reason why the cycle stability is improved compared to known lithium-based anodes with aluminum, as the sheet-like (i.e., cohesive compared to aluminum powder) metal structure of the aluminum improves the mechanical properties of the negative electrode during cycling.

[0010] The higher power density (i.e., a more homogeneous current density distribution and an increase in electrical power) compared to known aluminum-based negative electrodes results from the presence of carbon in the negative electrode. The higher electrical power is due to the fact that alkali metal ions (e.g., lithium ions) can intercalate and deintercalate more rapidly in carbon than alkali metal ions (e.g., lithium ions) can diffuse into aluminum. The alkali metal ions that diffuse into aluminum form an alloy with the aluminum (e.g., a Li-Al alloy), and the diffusion kinetics of the alkali metal ions are further slowed by the resulting alloy, thus reducing the power density. This decrease in power density can be compensated for by the presence of carbon in the negative electrode.Since the negative electrode produced by this process contains both carbon and aluminum, the reaction and diffusion kinetics complement each other perfectly. The carbon in the negative electrode is also a reason why the cycle stability is improved compared to known aluminum-based anodes, as the carbon mechanically supports the aluminum and thus reduces or completely prevents aluminum delamination and the formation of electrically isolated areas due to volume changes during cycling. This effect is enhanced if the process involves coating both sides of the planar metal structure with carbon, as this results in a double-sided "encapsulation" of the aluminum.

[0011] An improvement in cycle stability and hysteresis properties compared to a C-Si anode results from the use of aluminum instead of silicon in the negative electrode according to the invention, which causes a low volume expansion during cycling and allows the entire SOC range to be improved.

[0012] An improvement in cycle stability in a cell containing an LMO cathode and a carbon anode results from the presence of aluminum as an additional component of the anode, since the aluminum acts as Mn 2+ -catcher can act. Due to the "catching" of Mn 2+ The aluminum in the anode can slow down or even completely prevent the clogging of the carbon intercalation channels by manganese and the associated anode degradation, thus increasing cycle stability.

[0013] In a preferred embodiment of the method, the first planar metal structure contains or consists of aluminum or an aluminum alloy, wherein the aluminum alloy preferably contains at least 50 wt.% aluminum, and the second planar metal structure contains or consists of a metal that has a higher Vickers hardness than aluminum. The first planar metal structure is pressed into the carbon coating of the second planar metal structure over a distance that corresponds at most to the determined height of the carbon coating.

[0014] In this preferred embodiment, the second planar metal structure can contain or consist of a metal selected from the group consisting of nickel, copper, stainless steel, and combinations and alloys thereof. The metal preferably contains or consists of copper, wherein the second planar metal structure is in particular a copper foil.

[0015] In an alternative, preferred embodiment of the method, the first planar metal structure contains or consists of a metal having a higher Vickers hardness than aluminum, and the second planar metal structure contains or consists of aluminum or an aluminum alloy, wherein the aluminum alloy preferably contains at least 50 wt.% aluminum. Here, the first planar metal structure is pressed into the carbon coating of the second planar metal structure over a distance that is at least equal to the specified height of the carbon coating. Preferably, this distance corresponds to at least the sum of the specified height of the carbon coating and the specified height of the second planar metal structure, and the plurality of openings on the underside of the first planar metal structure are additionally filled with aluminum or the aluminum alloy of the second planar metal structure.This section preferably corresponds to the sum of the specified height of the carbon coating, the specified height of the second planar metal structure, and a specified height of a further carbon coating applied to, or already present on, the underside of the second planar metal structure, wherein the multitude of openings on the underside of the first planar metal structure are additionally filled with carbon from the further carbon coating. The deeper the first planar metal structure is pressed in, the more compact and mechanically stable the negative electrode becomes.

[0016] In this alternative, preferred embodiment, the first planar metal structure can contain or consist of a metal selected from the group consisting of nickel, copper, stainless steel, and combinations and alloys thereof, wherein the metal preferably contains or consists of stainless steel. In particular, the first planar metal structure is a stainless steel mesh with a plurality of openings on the underside of the stainless steel mesh, a stainless steel expanded metal with a plurality of openings on the underside of the stainless steel expanded metal, or a stainless steel foil with a plurality of openings on the underside of the stainless steel foil.

[0017] In the inventive method, the first planar metal structure can have a plurality of through openings extending from the underside to the top side of the first planar metal structure. This has the advantage that no air inclusions can occur or air is compressed when the first planar metal structure is pressed into the carbon coating of the second planar metal structure, which can increase the mechanical stability of the produced negative electrode and result in a more stable and efficient electrical contact.

[0018] Furthermore, the first planar metal structure can be selected from the group consisting of metal foil, expanded metal, perforated sheet metal, metal mesh and combinations thereof.

[0019] Furthermore, the first planar metal structure on the top and / or bottom surface can have a nucleation layer and be in contact with this nucleation layer. The nucleation layer can contain or consist of a metal selected from the group consisting of zinc, tin, indium, and combinations thereof. The nucleation layer preferably has a height, in a direction perpendicular to the top and / or bottom surface of the nucleation layer, in the range of > 0 and < 1 µm.

[0020] Apart from that, the first planar metal structure can have a height, in a direction perpendicular to the top and / or bottom of the first planar metal structure, in the range of 1 to 100 µm, preferably 5 to 50 µm, particularly preferably 10 to 40 µm.

[0021] Furthermore, the first planar metal structure can have a surface structuring on the top and / or bottom, wherein the surface structuring is preferably selected from the group consisting of brushed surface structuring, ribbed surface structuring, embossed surface structuring, etched surface structuring, laser-cut surface structuring and combinations thereof.

[0022] In the method according to the invention, the second planar metal structure can be selected from the group consisting of metal foil, expanded metal, perforated sheet, metal mesh and combinations thereof.

[0023] Furthermore, the second planar metal structure can have a nucleation layer on its top and / or bottom surface and contact this nucleation layer. The nucleation layer can contain or consist of a metal selected from the group consisting of zinc, tin, indium, and combinations thereof. The nucleation layer preferably has a height, in a direction perpendicular to the top and / or bottom surface of the nucleation layer, in the range of > 0 and < 1 µm.

[0024] Furthermore, the second planar metal structure can have a height in the range of 1 to 100 µm, preferably 2 to 50 µm, particularly preferably 5 to 40 µm, optionally 10 to 20 µm, in a direction perpendicular to the top and / or bottom of the second planar metal structure.

[0025] Apart from that, the second planar metal structure can have a surface structuring on the top and / or bottom, wherein the surface structuring is preferably selected from the group consisting of brushed surface structuring, ribbed surface structuring, embossed surface structuring, etched surface structuring, laser-cut surface structuring and combinations thereof.

[0026] In the inventive method, the carbon coating, optionally also a further carbon coating, which is applied to or is applied to the underside of the second planar metal structure, can contain or consist of a carbon selected from the group consisting of activated carbon, graphite, graphene, conductive carbon black, carbon nanotubes, carbon nanowires, carbon C65, carbon C45 and combinations thereof.

[0027] Furthermore, the carbon coating, optionally also a further carbon coating, which is applied to or is on the underside of the second planar metal structure, can have a height in the range of 1 to 100 µm, preferably in the range of 2 to 50 µm, particularly preferably in the range of 5 to 40 µm.

[0028] In a preferred embodiment, pressing the first planar metal structure into the carbon coating of the second planar metal structure comprises exerting a mechanical pressure of at least 390 kg / cm². 2 preferably in the range of 2500 to 6000 kg / cm² 2 , onto the top surface of the first planar metal structure, or consists thereof. The mechanical pressure is particularly preferably applied using a cold lever press for a duration of 10 to 20 seconds at a temperature in the range of 20 to 30 °C.

[0029] According to the invention, a negative electrode suitable for use in a galvanic cell is further provided, containing or consisting of: a) a first planar metal structure having a planar top and a planar bottom and having a certain height in a direction perpendicular to the top and bottom, wherein the first planar metal structure has a plurality of openings on its bottom which extend from the bottom towards the top of the first planar metal structure; b) a second planar metal structure having a planar top and a planar bottom and having a certain height in a direction perpendicular to the top and bottom, wherein at least the top of the second planar metal structure has a carbon coating, wherein the carbon coating has a planar top and a planar bottom and has a certain height in a direction perpendicular to the top and bottom, and wherein the bottom of the carbon coating contacts the top of the second planar metal structure;characterized in that the first planar metal structure is pressed into the carbon coating of the second planar metal structure, such that the plurality of openings on the underside of the first planar metal structure are at least partially filled with carbon from the carbon coating of the second planar metal structure, wherein the first planar metal structure or the second planar metal structure contains or consists of aluminum or an aluminum alloy.

[0030] In a preferred embodiment of the negative electrode, the first planar metal structure contains or consists of aluminum or an aluminum alloy, wherein the aluminum alloy preferably contains at least 50 wt.% aluminum, and the second planar metal structure contains or consists of a metal that has a higher Vickers hardness than aluminum. The first planar metal structure is pressed into the carbon coating of the second planar metal structure over a distance that corresponds at most to the determined height of the carbon coating.

[0031] In this preferred embodiment, the second planar metal structure may contain or consist of a metal selected from the group consisting of nickel, copper, stainless steel and combinations and alloys thereof, wherein the metal preferably contains or consists of copper.

[0032] In an alternative, preferred embodiment of the negative electrode, the first planar metal structure contains or consists of a metal having a higher Vickers hardness than aluminum, and the second planar metal structure contains or consists of aluminum or an aluminum alloy, wherein the aluminum alloy preferably contains at least 50 wt.% aluminum. Here, the first planar metal structure is pressed into the carbon coating of the second planar metal structure over a distance that is at least equal to the specified height of the carbon coating. This distance preferably corresponds to at least the sum of the specified height of the carbon coating and the specified height of the second planar metal structure, and the plurality of openings on the underside of the first planar metal structure are additionally filled with aluminum or the aluminum alloy of the second planar metal structure.The said section particularly preferably corresponds to a sum of the specified height of the carbon coating, the specified height of the second planar metal structure and a specified height of a further carbon coating applied to the underside of the second planar metal structure, and the plurality of openings on the underside of the first planar metal structure are additionally filled with carbon from the further carbon coating.

[0033] In this alternative, preferred embodiment, the first planar metal structure can contain or consist of a metal selected from the group consisting of nickel, copper, stainless steel, and combinations and alloys thereof, wherein the metal preferably contains or consists of stainless steel. In particular, the first planar metal structure is a stainless steel mesh with a plurality of openings on the underside of the stainless steel mesh, a stainless steel expanded metal with a plurality of openings on the underside of the stainless steel expanded metal, or a stainless steel foil with a plurality of openings on the underside of the stainless steel foil.

[0034] In the negative electrode according to the invention, the first planar metal structure can have a plurality of through openings extending from the underside to the top side of the first planar metal structure.

[0035] Furthermore, the first planar metal structure can be selected from the group consisting of metal foil, expanded metal, perforated sheet metal, metal mesh and combinations thereof.

[0036] Furthermore, the first planar metal structure on the top and / or bottom surface can have a nucleation layer and be in contact with this nucleation layer. The nucleation layer can contain or consist of a metal selected from the group consisting of zinc, tin, indium, and combinations thereof. Preferably, the nucleation layer has a height, in a direction perpendicular to the top and / or bottom surface of the nucleation layer, in the range of > 0 and < 1 µm.

[0037] Apart from that, the first planar metal structure can have a height, in a direction perpendicular to the top and / or bottom of the first planar metal structure, in the range of 1 to 100 µm, preferably 5 to 50 µm, particularly preferably 10 to 40 µm.

[0038] Furthermore, the first planar metal structure can have a surface structuring on the top and / or bottom, wherein the surface structuring is preferably selected from the group consisting of brushed surface structuring, ribbed surface structuring, embossed surface structuring, etched surface structuring, laser-cut surface structuring and combinations thereof.

[0039] In the negative electrode according to the invention, the second planar metal structure can be selected from the group consisting of metal foil, expanded metal, perforated sheet, metal mesh and combinations thereof.

[0040] Furthermore, the second planar metal structure can have a nucleation layer on its top and / or bottom surface and contact this nucleation layer. The nucleation layer can contain or consist of a metal selected from the group consisting of zinc, tin, indium, and combinations thereof. Preferably, the nucleation layer has a height, in a direction perpendicular to the top and / or bottom surface of the nucleation layer, in the range of > 0 and < 1 µm.

[0041] Furthermore, the second planar metal structure can have a height in the range of 1 to 100 µm, preferably 2 to 50 µm, particularly preferably 5 to 40 µm, optionally 10 to 20 µm, in a direction perpendicular to the top and / or bottom of the second planar metal structure.

[0042] Apart from that, the second planar metal structure can have a surface structuring on the top and / or bottom, wherein the surface structuring is preferably selected from the group consisting of brushed surface structuring, ribbed surface structuring, embossed surface structuring, etched surface structuring, laser-cut surface structuring and combinations thereof.

[0043] The carbon coating of the negative electrode, optionally also a further carbon coating applied to the underside of the second planar metal structure, can contain or consist of carbon selected from the group consisting of activated carbon, graphite, graphene, conductive carbon black, carbon nanotubes, carbon nanowires, carbon C65, carbon C45 and combinations thereof.

[0044] Furthermore, the carbon coating, optionally also a further carbon coating applied to the underside of the second planar metal structure, can have a height in the range of 1 to 100 µm, preferably in the range of 2 to 50 µm, particularly preferably in the range of 5 to 40 µm.

[0045] The negative electrode according to the invention can be produced by the inventive method. Consequently, the negative electrode can have at least one feature that necessarily results from carrying out the inventive method.

[0046] For example, the negative electrode can be characterized by the fact that the first planar metal structure is embedded in the carbon coating of the second planar metal structure by exerting a mechanical pressure of at least 390 kg / cm². 2 preferably in the range of 2500 to 6000 kg / cm² 2, is pressed onto the top surface of the first flat metal structure. Mechanical pressure was particularly preferred when applied using a cold lever press for a duration of 10 to 20 seconds at a temperature in the range of 20 to 30 °C.

[0047] According to the invention, a galvanic cell is further provided, comprising a negative electrode according to the invention, a cathode, and an electrolyte. Preferably, the galvanic cell also includes a separator arranged between the negative electrode according to the invention and the cathode. Particularly preferably, the separator is faced with a planar metal structure containing or consisting of aluminum, or with a further carbon coating of the electrode.

[0048] Furthermore, the use of the galvanic cell according to the invention for energy supply is described. i) a mobile device, preferably a mobile phone, headphones, a vehicle, an aircraft and / or a ship; and / or ii) a stationary device, preferably a building; and / or iii) a medical device, preferably a hearing aid and / or a pacemaker; proposed.

[0049] The following figures are intended to explain the subject matter of the invention in more detail, without limiting it to the specific embodiments shown here.

[0050] Fig. Figure 1 shows a first embodiment of the method according to the invention. In this embodiment, a negative electrode is produced, which can be described as a C-Al anode 17 (here: graphite-aluminum expanded metal composite). First, a carbon layer 10 (here: graphite layer) is applied to the top surface 7 of a second planar metal structure 6 (here: copper conductive foil) (e.g., by spraying or doctor blade application). Subsequently, a first planar metal structure 1, which here consists of aluminum and has continuous openings 5, i.e., is a perforated aluminum expanded metal foil, is positioned on the carbon layer 10 and pressed into the carbon layer 10 by compression 14, whereby the continuous openings 5 ​​of the first planar metal structure 1 are at least partially filled with the carbon of the carbon layer 10, and a C-Al anode 17 is formed.The C-Al anode 17 exhibits both high-performance properties due to the graphite contribution and high-energy properties due to the aluminum contribution. The process thus provides a negative electrode with high cycle stability and high energy density. Furthermore, the process is simple and cost-effective.

[0051] Fig. Figure 2 shows a second variant of the method according to the invention. In this variant of the method, a negative electrode is produced, which can be described as a C-Al-C anode 18 (here: graphitized aluminum foil on both sides). First, a first carbon layer 10 (here: graphite layer) is arranged on the top side 7 of a second planar metal structure 6, which here consists of aluminum, i.e., is an aluminum foil, and a second carbon layer 15 is arranged on the bottom side 8 of the second planar metal structure 6 (e.g., by spraying or doctor blade application).Subsequently, a first planar metal structure 1 (here: stainless steel mesh 1), which has continuous openings 5 ​​and later serves as a current collector, is positioned on the first carbon layer 10 and pressed into the first carbon layer 10 and also into the second planar metal structure 6 by pressing 14. This causes the continuous openings 5 ​​of the first planar metal structure 1 to be at least partially filled with the carbon of the carbon layer 10 and the aluminum of the second planar metal structure 6, creating a C-Al-C anode 18. Due to the graphite component, the C-Al-C anode 18 exhibits both high-performance properties and high-energy properties due to the aluminum component. The process thus provides a negative electrode that exhibits high cycle stability and high energy density. The cycle stability is higher than that in [reference missing]. Fig.The C-Al anode shown in Figure 1 is even further improved, as the graphite layer 3 present on both sides can prevent aluminum degradation. Furthermore, this variant of the process is also simple and cost-effective. Reference symbol list: 1. First flat metal structure; 2 Top side of the first flat metal structure; 3 Underside of the first flat metal structure; 4 Height of the first planar metal structure; 5 Continuous opening(s) of the first planar metal structure; 6 second flat metal structure; 7 Top side of the second planar metal structure; 8 Underside of the second flat metal structure; 9 Height of the second planar metal structure; 10 first carbon layer (or carbon coating) on ​​the top side of the second planar metal structure; 11 Top side of the first carbon coating; 12 Underside of the first carbon coating; 13 Height of the first carbon coating; 14 Pressing the first planar metal structure at least into the first carbon coating; 15 second (or further) carbon layer (or carbon coating) on ​​the underside of the second planar metal structure; 16 Height of the second (or further) carbon coating; 17 first negative electrode (C-Al anode); 18 second negative electrode (C-Al-C anode). QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] CN 107623119 A

[0002] Cited non-patent literature

[0000] Jin, Y. et al., Advanced Energy Materials, Vol. 7, Issue 23, 1700715, pp. 1-17

[0003]

Claims

[1] A method for producing a negative electrode for a galvanic cell, comprising a) providing a first planar metal structure having a planar top side and a planar bottom side and having a specific height in a direction perpendicular to the top side and bottom side, wherein the first planar metal structure has a plurality of openings on its planar bottom side extending from the bottom side toward the top side of the first planar metal structure; b) providing a second planar metal structure having a planar top side and a planar bottom side and having a specific height in a direction perpendicular to the top side and bottom side, wherein at least the top side of the second planar metal structure has a carbon coating, wherein the carbon coating has a planar top side and a planar bottom side and has a specific height in a direction perpendicular to the top side and bottom side, wherein the bottom side of the carbon coating contacts the top side of the second planar metal structure; characterized bythat the first planar metal structure is pressed at least into the carbon coating of the second planar metal structure and the plurality of openings on the planar underside of the first planar metal structure are filled at least in regions with carbon from the carbon coating of the second planar metal structure, wherein the first planar metal structure or the second planar metal structure contains or consists of aluminum or an aluminum alloy. [2] Method according to claim 1, characterized byin that the first planar metal structure contains or consists of aluminum or an aluminum alloy, wherein the aluminum alloy preferably contains at least 50% by weight of aluminum, and the second planar metal structure contains or consists of a metal which has a higher Vickers hardness than aluminum, wherein the first planar metal structure is pressed into the carbon coating of the second planar metal structure over a distance which corresponds at most to the determined height of the carbon coating. [3] Method according to claim 2, characterized by that the second planar metal structure contains or consists of a metal selected from the group consisting of nickel, copper, stainless steel and combinations and alloys thereof, wherein the metal preferably contains or consists of copper, wherein the second planar metal structure is in particular a copper foil. [4] Method according to claim 1, characterized bythat the first planar metal structure contains or consists of a metal that has a higher Vickers hardness than aluminum, and the second planar metal structure contains or consists of aluminum or an aluminum alloy, wherein the aluminum alloy preferably contains at least 50 wt.% aluminum, wherein the first planar metal structure is pressed into the carbon coating of the second planar metal structure over a distance that corresponds at least to the specific height of the carbon coating, wherein the distance preferably corresponds at least to a sum of the specific height of the carbon coating and the specific height of the second planar metal structure, and the plurality of openings on the underside of the first planar metal structure are additionally filled with aluminum or the aluminum alloy of the second planar metal structure, wherein the distance particularly preferably corresponds to a sum of the specific height of the carbon coating,the specific height of the second planar metal structure and a specific height of a further carbon coating that is or is applied to the underside of the second planar metal structure, and the plurality of openings on the underside of the first planar metal structure are additionally filled with carbon of the further carbon coating. [5] Method according to claim 4, characterized bythat the first planar metal structure contains or consists of a metal selected from the group consisting of nickel, copper, stainless steel and combinations and alloys thereof, wherein the metal preferably contains or consists of stainless steel, wherein the first planar metal structure is in particular a stainless steel mesh with a plurality of openings on the underside of the stainless steel mesh, a stainless steel expanded metal with a plurality of openings on the underside of the stainless steel expanded metal or a stainless steel foil with a plurality of openings on the underside of the stainless steel foil. [6] Method according to one of the preceding claims, characterized by that the first flat metal structure i) has a plurality of through openings extending from the bottom to the top of the first sheet-like metal structure; and / or ii) is selected from the group consisting of metal foil, expanded metal, perforated metal, metal mesh and combinations thereof; and / or iii) has a nucleation layer on the top and / or bottom side and contacts this nucleation layer, wherein the nucleation layer contains or consists of a metal selected from the group consisting of zinc, tin, indium and combinations thereof, wherein the nucleation layer preferably has a height, in a direction perpendicular to the top and / or bottom side of the nucleation layer, in the range of > 0 and < 1 µm; and / or iv) has a height, in a direction perpendicular to the top and / or bottom of the first planar metal structure, in the range of 1 to 100 µm, preferably 5 to 50 µm, particularly preferably 10 to 40 µm; and / or v) has a surface structuring on the top and / or bottom side, wherein the surface structuring is preferably selected from the group consisting of brushed surface structuring, grooved surface structuring, embossed surface structuring, etched surface structuring, lasered surface structuring and combinations thereof. [7] Method according to one of the preceding claims, characterized by that the second flat metal structure i) is selected from the group consisting of metal foil, expanded metal, perforated metal, metal mesh and combinations thereof; and / or ii) has a nucleation layer on the top and / or bottom side and contacts this nucleation layer, wherein the nucleation layer contains or consists of a metal selected from the group consisting of zinc, tin, indium and combinations thereof, wherein the nucleation layer preferably has a height, in a direction perpendicular to the top and / or bottom side of the nucleation layer, in the range of > 0 and < 1 µm; and / or iii) in a direction perpendicular to the top and / or bottom of the second planar metal structure, has a height in the range of 1 to 100 µm, preferably 2 to 50 µm, particularly preferably 5 to 40 µm, optionally 10 to 20 µm; and / or iv) has a surface structuring on the top and / or bottom side, wherein the surface structuring is preferably selected from the group consisting of brushed surface structuring, grooved surface structuring, embossed surface structuring, etched surface structuring, lasered surface structuring and combinations thereof. [8] Method according to one of the preceding claims, characterized by that the carbon coating, optionally also a further carbon coating, which is or is applied to the underside of the second flat metal structure, i) contains or consists of a carbon selected from the group consisting of activated carbon, graphite, graphene, conductive carbon black, carbon nanotubes, carbon nanowires, carbon C65, carbon C45 and combinations thereof; and / or ii) has a height in the range of 1 to 100 µm, preferably in the range of 2 to 50 µm, particularly preferably in the range of 5 to 40 µm. [9] Method according to one of the preceding claims, characterized by that the pressing of the first planar metal structure into the carbon coating of the second planar metal structure involves exerting a mechanical pressure of at least 390 kg / cm 2 , preferably in the range of 2500 to 6000 kg / cm 2 , on the upper side of the first planar metal structure or consists thereof, wherein the mechanical pressure is particularly preferably applied via a cold lever press for a duration of 10 to 20 seconds at a temperature in the range of 20 to 30 °C. [10] Negative electrode for a galvanic cell, containing or consisting of: a) a first planar metal structure having a planar top surface and a planar bottom surface and having a certain height in a direction perpendicular to the top surface and bottom surface, the first planar metal structure having a plurality of openings on its bottom surface extending from the bottom surface toward the top surface of the first planar metal structure; b) a second planar metal structure having a planar top side and a planar bottom side and having a specific height in a direction perpendicular to the top side and bottom side, wherein at least the top side of the second planar metal structure has a carbon coating, wherein the carbon coating has a planar top side and a planar bottom side and has a specific height in a direction perpendicular to the top side and bottom side, wherein the bottom side of the carbon coating contacts the top side of the second planar metal structure; characterized byin that the first planar metal structure is pressed into the carbon coating of the second planar metal structure, so that the plurality of openings on the underside of the first planar metal structure are at least partially filled with carbon from the carbon coating of the second planar metal structure, wherein the first planar metal structure or the second planar metal structure contains or consists of aluminum or an aluminum alloy. [11] Electrode according to claim 10, characterized byin that the first planar metal structure contains or consists of aluminum or an aluminum alloy, wherein the aluminum alloy preferably contains at least 50% by weight of aluminum, and the second planar metal structure contains or consists of a metal which has a higher Vickers hardness than aluminum, wherein the first planar metal structure is pressed into the carbon coating of the second planar metal structure over a distance which corresponds at most to the determined height of the carbon coating. [12] Electrode according to claim 11, characterized by that the second planar metal structure contains or consists of a metal selected from the group consisting of nickel, copper, stainless steel and combinations and alloys thereof, wherein the metal preferably contains or consists of copper. [13] Electrode according to claim 10, characterized bythat the first planar metal structure contains or consists of a metal that has a higher Vickers hardness than aluminum, and the second planar metal structure contains or consists of aluminum or an aluminum alloy, wherein the aluminum alloy preferably contains at least 50 wt.% aluminum, wherein the first planar metal structure is pressed into the carbon coating of the second planar metal structure over a distance that corresponds at least to the specific height of the carbon coating, wherein the distance preferably corresponds at least to a sum of the specific height of the carbon coating and the specific height of the second planar metal structure, and the plurality of openings on the underside of the first planar metal structure are additionally filled with aluminum or the aluminum alloy of the second planar metal structure, wherein the distance particularly preferably corresponds to a sum of the specific height of the carbon coating,the specific height of the second planar metal structure and a specific height of a further carbon coating applied to the underside of the second planar metal structure, and the plurality of openings on the underside of the first planar metal structure are additionally filled with carbon of the further carbon coating. [14] Electrode according to claim 13, characterized bythat the first planar metal structure contains or consists of a metal selected from the group consisting of nickel, copper, stainless steel and combinations and alloys thereof, wherein the metal preferably contains or consists of stainless steel, wherein the first planar metal structure is in particular a stainless steel mesh with a plurality of openings on the underside of the stainless steel mesh, a stainless steel expanded metal with a plurality of openings on the underside of the stainless steel expanded metal or a stainless steel foil with a plurality of openings on the underside of the stainless steel foil. [15] Electrode according to one of claims 10 to 14, characterized by that the first flat metal structure i) has a plurality of through openings extending from the bottom to the top of the first sheet-like metal structure; and / or ii) is selected from the group consisting of metal foil, expanded metal, perforated metal, metal mesh and combinations thereof; and / or iii) has a nucleation layer on the top and / or bottom side and contacts this nucleation layer, wherein the nucleation layer contains or consists of a metal selected from the group consisting of zinc, tin, indium and combinations thereof, wherein the nucleation layer preferably has a height, in a direction perpendicular to the top and / or bottom side of the nucleation layer, in the range of > 0 and < 1 µm; and / or iv) has a height, in a direction perpendicular to the top and / or bottom of the first planar metal structure, in the range of 1 to 100 µm, preferably 5 to 50 µm, particularly preferably 10 to 40 µm; and / or v) has a surface structuring on the top and / or bottom side, wherein the surface structuring is preferably selected from the group consisting of brushed surface structuring, grooved surface structuring, embossed surface structuring, etched surface structuring, lasered surface structuring and combinations thereof. [16] Electrode according to one of claims 10 to 15, characterized by that the second flat metal structure i) is selected from the group consisting of metal foil, expanded metal, perforated metal, metal mesh and combinations thereof; and / or ii) has a nucleation layer on the top and / or bottom side and contacts this nucleation layer, wherein the nucleation layer contains or consists of a metal selected from the group consisting of zinc, tin, indium and combinations thereof, wherein the nucleation layer preferably has a height, in a direction perpendicular to the top and / or bottom side of the nucleation layer, in the range of > 0 and < 1 µm; and / or iii) in a direction perpendicular to the top and / or bottom of the second planar metal structure, has a height in the range of 1 to 100 µm, preferably 2 to 50 µm, particularly preferably 5 to 40 µm, optionally 10 to 20 µm; and / or iv) has a surface structuring on the top and / or bottom side, wherein the surface structuring is preferably selected from the group consisting of brushed surface structuring, grooved surface structuring, embossed surface structuring, etched surface structuring, lasered surface structuring and combinations thereof. [17] Electrode according to one of claims 10 to 16, characterized by that the carbon coating, optionally also a further carbon coating, which is applied to the underside of the second flat metal structure, i) contains or consists of a carbon selected from the group consisting of activated carbon, graphite, graphene, conductive carbon black, carbon nanotubes, carbon nanowires, carbon C65, carbon C45 and combinations thereof; and / or ii) has a height in the range of 1 to 100 µm, preferably in the range of 2 to 50 µm, particularly preferably in the range of 5 to 40 µm. [18] Electrode according to one of claims 10 to 17, characterized by that the first planar metal structure is pressed into the carbon coating of the second planar metal structure by exerting a mechanical pressure of at least 390 kg / cm 2 , preferably in the range of 2500 to 6000 kg / cm 2 , onto the upper side of the first planar metal structure, wherein the mechanical pressure was particularly preferably applied via a cold lever press for a period of 10 to 20 seconds at a temperature in the range of 20 to 30 °C. [19] Galvanic cell comprising a negative electrode according to one of claims 10 to 18, a cathode and an electrolyte, wherein the galvanic cell preferably further comprises a separator arranged between the negative electrode and the cathode, wherein particularly preferably a flat metal structure containing or consisting of aluminum or a further carbon coating of the electrode faces the separator. [20] Use of the galvanic cell according to claim 19 for energy supply i) a mobile device, preferably a mobile phone, a headset, a vehicle, an aircraft and / or a ship; and / or ii) a stationary device, preferably a building; and / or iii) a medical device, preferably a hearing aid and / or a pacemaker.

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